Active EMC filter connectable between an electric power source and an electric load. The filter has capacitors (C×N, C×U) connected between active conductors of the power source and a star point electric node. A filter capacitor (Cst, CstU) is connected between the star point and ground. A half-bridge has two switching devices (T3, T4; T1, T2) connected in cascade between a positive supply voltage and a negative supply voltage. A smoothing circuit (RgN, LgN; RgU, RgU) is connected between a common node of the switching devices and the star point. A control unit (Drive_N, Drive_U) drives the switching devices (T3, T4; T1, T2) digitally either in an ON-state or in an OFF-state, such as to limit a leakage current.
Legal claims defining the scope of protection, as filed with the USPTO.
1. Active EMC filter connectable between an electric power source and an electric load, comprising: capacitors connected between conductors of said power source and a star point electric node; a filter capacitor connected between said star point and ground; a half-bridge comprising two switching devices connected in cascade between a positive supply voltage and a negative supply voltage; a smoothing circuit connected between a common node of said switching devices and said star point; and a control unit driving said switching devices digitally either in an ON-state or in an OFF-state, such as to limit a leakage current.
2. The active EMC filter of claim 1 , wherein the switching devices are in the ON-state in saturation.
3. The active EMC filter of claim 1 , wherein the smoothing circuit comprises an inductor.
4. The active EMC filter of claim 3 , wherein the smoothing circuit comprises a resistor in parallel to the inductor of the smoothing circuit.
5. The active FMC filter of claim 1 , wherein the control unit is sensitive to the voltage present at the star point.
6. The active EMC filter of claim 1 , wherein the power source is a three-phase AC source, or a DC power source.
7. The active EMC filter of claim 1 , wherein the control unit is sensitive to the magnetic flux in and/or voltage across a choke that is included in the LMC filter.
8. The active EMC filter of claim 7 , wherein the choke is connected between the electric power source and the load.
9. The active EMC filter of claim 8 , the power source being a three-phase AC source, and wherein the choke is current-compensated.
10. EMC management system comprising a three-phase AC source, connected by a first active EMC filter to a rectifying bridge, connected by DC link that includes a second active EMC filter to a switched bridge, which is driven so as to generate a variable AC supply, wherein the first active EMC filter comprises: first capacitors connected between conductors connecting said power source with the rectifying bridge and a first star point electric node; a first filter capacitor connected between said first star point and ground; a first half-bridge comprising two first switching devices connected in cascade between a positive supply voltage and a negative supply voltage; a first smoothing circuit connected between a common node of said first switching devices and said first star point; and a first control unit driving said first switching devices digitally either in an ON-state or in an OFF-state, such as to limit a leakage current; wherein the second active EMC filter comprises: second capacitors connected between conductors connecting said rectifying bridge with said inverter and a second star point electric node; a second filter capacitor connected between said second star point and ground; a second half-bridge comprising two second switching devices connected in cascade between a positive supply voltage and a negative supply voltage; a second smoothing circuit connected between a common node of said second switching devices and said second star point; and a second control unit driving said second switching devices digitally either in an ON-state or in an OFF-state, such as to limit a leakage current.
11. The EMC management system of claim 10 , wherein the switching devices of the first active EMC filter and of the second active EMC filter are in the ON-state in saturation.
12. The EMC management system of claim 10 , wherein the first smoothing circuit and the second smoothing circuit comprise an inductor.
13. The EMC management system of claim 10 , wherein the first control unit is sensitive to the voltage present at the first star point and the second control unit is sensitive to the voltage present at the second star point.
14. The EMC management system of claim 10 , wherein the first control unit is sensitive to the magnetic flux in and/or voltage across a choke that is included in the conductor between the AC source and the rectifying bridge.
15. The EMC management system of claim 14 , wherein the choke is current-compensated.
Cooperative Patent Classification codes for this invention. Click any code to explore related patents in that topic.
April 15, 2014
September 8, 2015
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